Retinoblastoma is a disease in which malignant (cancer) cells form in the tissues of the retina.
The retina is the nervetissue that lines the inside of the back of the eye. The retina senses light and sends images to the brain by way of the optic nerve.
Anatomy of the eye, showing the outside and inside of the eye including the sclera, cornea, iris, ciliary body, choroid, retina, vitreous humor, and optic nerve. The vitreous humor is a gel that fills the center of the eye.
Although retinoblastoma may occur at any age, it usually occurs in children younger than 5 years, most often younger than 2 years. The tumor may be in one eye or in both eyes. Retinoblastoma rarely spreads from the eye to nearby tissue or other parts of the body.
Retinoblastoma is sometimes caused by a gene mutation passed from the parent to the child.
Retinoblastoma is sometimes inherited (passed from the parent to the child). Retinoblastoma that is caused by an inherited genemutation is called hereditary retinoblastoma. It usually occurs at a younger age than retinoblastoma that is not inherited. Retinoblastoma that occurs in only one eye is usually not inherited. Retinoblastoma that occurs in both eyes is thought to be inherited.
When hereditary retinoblastoma first occurs in only one eye, there is a chance it will develop later in the other eye. After diagnosis of retinoblastoma in one eye, regular follow-up exams of the healthy eye should be done every 2 to 4 months for at least 28 months. After treatment for retinoblastoma is finished, it is important that follow-up exams continue until the child is 5 years old.
Treatment for both types of retinoblastoma should include genetic counseling (a discussion with a trained professional about inherited diseases). The parents of a child with retinoblastoma should have an eye exam by an ophthalmologist (a doctor with special training in diseases of the eye) and genetic counseling about whether they should be tested for the gene that causes retinoblastoma and the risk of the child's brothers or sisters developing retinoblastoma. The child's brothers and sisters also should have regular eye exams by an ophthalmologist until age 5 years.
A child who has hereditary retinoblastoma is at risk for developing trilateral retinoblastoma and other cancers.
A child who has hereditary retinoblastoma is at risk for developing pineal tumors in the brain. This is called trilateral retinoblastoma and usually occurs more than 20 months after retinoblastoma is diagnosed. Regular screening using MRI (magnetic resonance imaging) every 6 months for 5 years may be recommended for a child with hereditary retinoblastoma or with retinoblastoma in one eye and a family history of the disease. CT scans (computerized tomography) should not be used for routine screening to avoid exposing the child to ionizing radiation. Hereditary retinoblastoma also increases the child's risk of developing other types of cancer such as bone or soft tissue sarcoma or melanoma in later years. Regular follow-up exams are important.